In a small bowl, combine cracker crumbs and sugar; stir in egg white and butter. Press onto the bottom and up the sides of a 9-in. pie plate coated with cooking spray. Bake at 375° for 6-8 minutes or until set. Cool completely on a wire rack.
Spread 2-2/3 cups of frozen yogurt into the crust. Sprinkle with half of the toffee bits; drizzle with half of caramel. Repeat with remaining yogurt, toffee and caramel. Cover and freeze for 8 hours or overnight. Remove from the freezer 15 minutes before serving.